Functional multilayer anisotropic conductive adhesive laminate

ABSTRACT

A functional multilayer anisotropic conductive adhesive film, capable of bonding and package 0.18-0.13 micron IC chips and high density COF, includes a monomer layer, a reinforcing layer, a low-temperature, hot-melt resin layer, and a conductive particle layer, successively bonded by coating and drying processes. The monomer layer comprises a copolymer of butyl acrylate, methyl acrylate, glycol acrylate, and tetramethyl butyl peroxy-2-ethyl hexanoate. The reinforcing layer comprises long chain imidazole derivatives. The hot-melt resin layer comprises polymer of tocopheroxyl, novolac epoxy, acrylic rubbers and elastic mixture of acrylic rubbers and styrene-butadiene rubbers. The conductive particle layer comprises conductive particles and micro-encapsulating resin for receiving the conductive particles. Diameter of the conductive particles is selected from the group consisting of 3.00 μm±0.05, 3.25 μm±0.05, 3.50 μm±0.05, 3.75 μm±0.05 and 4.00 μm±0.05.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention generally relates to a copolymer resin, moreparticularly the present invention relates to an improved functionalmultilayer anisotropic conductive adhesive film (ACAF) and itspreparation method.

2. Background of the Invention

A need for reduced weight and thickness has recently arose in connectionwith electronic equipment and devices containing mounted IC chipsbecause of new developments related to such electronic equipment, andthere is also a need of functional connection stuffs for higher densityin boards for mounting such IC chips. For example, in order to set microfillets directly engaged with IC chips, flexibility of the connectionstuffs is necessary for higher density in boards for mounting such ICchips, thus anisotropic conductive film (ACF) is applied for thispurpose. For the moment, ACF market scale is over 20 billions, andplaying an important role in social development.

During research and development of the ACF, in a typical pencilanisotropic conductive film, fillet distance and fillet width is about100 microns. TAP and COG apply different adhesive resins, couplingagents, and silicon powder fillers, which is disclosed in Japan Patents,JP03129607, JP08325543, and JP0931419. Other conventional preparationmethod for ACF is disclosed in patents, such as CN99807810.7, U.S. Pat.No. 5,240,761, U.S. Pat. No. 4,113,981, U.S. Pat. No. 5,180,888, U.S.Pat. No. 5,240,761, and U.S. Pat. No. 4,737,112, which says that:defining a plurality of dimples on a resin film, placing conductiveballs in dimples and then carrying coating process, thereby formingfilms demanded.

Assembling component without punching and welding is the key to realizehigh density fillet deployment, high speed connection and ultrathinassembly goals. However, on condition that fillet width of IC chips tobe connected is about 100 microns, the conventional ACF can barely meetsuch connection needs. Therefore anisotropic conductive adhesive films(ACAF) play an important role in connection between IC chips or IC chipsbased on transparent substrates and high density FPC or COF. Researcheson ACAF synchronizing with development of IC chips focus on optimumpreparation processes and stuff preparation so as to improve connectionproperty and lower cost. Meanwhile development of ACAF will facilitateexpansion of LCD market.

A typical ACF can refer to multilayer or two layer ACF, adopting layerto layer affixing means which is disclosed in Japan application No.2001171033, it says first and second layers are tapes formed by coatingprocess with resins in different proportion. Furthermore, Japanapplication No. 2001178511 discloses that four coating processes arepresented, a typical ACF is formed with first multilayer anisotropicconductive adhesive layer, second insulating layer, third anisotropicconductive adhesive layer, and fourth insulating layer. However, ACFobtained from the conventional preparation means mentioned above canhardly meet chip connection needs on condition that chip fillet width is10 microns.

In light of the foregoing, there is a very desirable need to improve thetypical anisotropic conductive adhesive film.

SUMMARY OF THE INVENTION

In general, the systems and methods of the invention have severalfeatures, no single one of which is solely responsible for its desirableattributes. Without limiting the scope of the invention as expressed bythe claims which follow, its more prominent features will now bediscussed briefly. After considering this discussion, and particularlyafter reading the section entitled “Detailed Description of CertainEmbodiments”, one will understand how the features of the system andmethods provide several advantages over traditional anisotropicconductive adhesive films.

In one aspect of the present invention, the object of the presentinvention is to provide an improved functional multilayer anisotropicconductive adhesive film capable of connection and package under microfillet distance and fillet width conditions, such as 0.18 micron, thefunctional multilayer anisotropic conductive adhesive film of thepresent invention keeps stable insulation between micro electrodes about10 microns distance.

In order to achieve the object mentioned above, an improved functionalmultilayer anisotropic conductive adhesive film and correspondingpreparation method are disclosed. The anisotropic conductive adhesivefilm (ACAF) includes a monomer layer, a reinforcing layer, alow-temperature, hot-melt resin layer, and a conductive particle layer,wherein the monomer layer, the reinforcing layer, the resin layer andthe conductive particle layer are successively bonded by coating anddrying processes. The monomer layer comprises a copolymer of butylacrylate, methyl acrylate, glycol acrylate, and tetramethyl butylperoxy-2-ethyl hexanoate. The reinforcing layer comprises long chainimidazole derivatives. The low-temperature, hot-melt resin layercomprises a polymer of tocopheroxyl, novolac epoxy, acrylic rubbers andelastic mixture of acrylic rubbers and styrene-butadiene rubbers. Theconductive particle layer comprises conductive particles and alow-temperature, hot-melt, micro-encapsulating resin for receiving theconductive particles, the diameter of the conductive particles selectedfrom the group consisting of 3.00 μm±0.05, 3.25 μm±0.05, 3.50 μm±0.05,3.75 μm±0.05 and 4.00 μm±0.05.

In the present invention, the conductive particles can be Michael Robert(brand) AV conductive particles.

In the polymerization of the low-temperature, hot-melt resin layer, thetocopheroxyl is referred to as YP-70, 10-30 parts by weight. The novolacepoxy is selected from the group consisting of F-55, F-51 and F-44,10-20 parts by weight. Bulk density of the acrylic rubbers is 0.48±0.1g/cc, volatility<1.0%, Tg−30° C., solution viscosity under temperatureof 25° C. is 5000-10000 mPa·S, 10-20 parts by weight. Thestyrene-butadiene rubbers have Mooney viscosity of natural rubber ML100°C.(1+4): 45-55%, stretching stress 300% (35 minutes): 14.1-18.6 MPa,tensile strength at a given elongation (35 minutes): >23.7 MPa, andelongation at break (35 minutes)>: 415%. The elastic mixture is 5-10parts by weight. The long chain imidazole derivatives is a synthesis of2,4-diamino-6-[-2-undecyl imidazolyl (1)]-ethyl-cis-triazine,1-cyanoethyl-2-undecyl-imidazole trimellitate, and isocyanatederivative; 0.75-5 parts by weight.

The content of the conductive particles is 30-40 parts by weight per 500parts by total weight of the anisotropic conductive adhesive film.

The solvent in the present invention is obtained by mixing toluene andethyl acetate with a weight ratio of 4:6, and a solution is preparedwith the reactant thereof by a weight concentration of 20%-40%.

The monomer in the monomer layer is applied to adjust the viscosity ofsurface coating layer on the anisotropic conductive adhesive film inaccordance with different IC chips, adjust flexibility, rigidity, andpreloading curing time. The copolymer in the monomer layer can beapplied to other resin solution in terms of composition or tolerancefactor of the monomer. Due to small molecular weight distribution range,little oligomer remains and little impurity remains characteristics ofthe monomer, by introducing functional matrix, together with isocyanateand epoxy ester, viscosity, intensity and waterlogging tolerance of theACAF is improved, at the same time achieving anti foaming purpose. Thecontent of the monomer in the monomer layer is 5-10 parts by weight per500 parts by the total weight of the anisotropic conductive adhesivefilm, wherein the weight ratio of the butyl acrylate, the methylacrylate, the glycol acrylates, and the tetramethyl butyl peroxy-2-ethylhexanoate is set in 7:3:2:1 according to the requirement ofcorresponding chipset.

The long chain imidazole derivatives in the reinforcing layer isobtained by the following processes: mixing the2,4-diamino-6-[-2-undecyl imidazolyl (1)]-ethyl-cis-triazine, and1-cyanoethyl-2-undecyl-imidazole trimellitate with a weight ratio of1:1, keeping them reacting for 3 hours. Use 30 parts by weight reactantfrom the mixing process, and then heating the reactant from the mixingprocess up to 50° C., adding 0.8 part by weight toluene-2,4-diisocyanateand 60 parts by weight solvent into the reactant, and keeping themreacting for 5 hours. Because the long chain imidazole derivativescontains a long carbon chain, its storage period is long and itpossesses fast curing characteristic under certain temperature andcertain time period by applying coating and micro encapsulationtechnique.

In the present invention, the thermal aging property of the elasticmixture is improved by steps of: mixing and preparing the acrylicrubbers and the styrene-butadiene rubbers with weight ratio of 10:5, andthen physically admixing trace meta-alkaline reinforcing agentcontaining silica, silane coupling agent, and quaternary ammonium salt,in accordance with a weight ratio of 1:0.2:0.3. The acrylic rubbersfunction as an impact modifier to improve shock strength, high thermalstability, and weather fastness. The elastic mixture facilitates theACAF lowering elastic ratio, buffering stress, improving viscosity, andimproving interface effect of the conductive particles in the resinsolution, so as to optimize uniform distribution of the conductiveparticles.

The method for preparing functional multilayer anisotropic conductiveadhesive film of the present invention, adopting suspensionpolymerization means, comprises the following steps: according to theabove mentioned formula, mixing and stirring tocopheroxyl, novolacepoxy, and a solvent in a reactor until the substances solved in thereactor; then adding and stirring acrylic rubbers and elastic mixture ofacrylic rubbers and styrene-butadiene rubbers into the reactant obtainedfrom previous step; and adding acrylic rubbers and a solvent into theadmixture obtained from previous step, dissolving and stirring; in theend waiting as viscosity of the polymer naturally reduces to a degreethat no more polymerization occurs, thus a coating stuff to be used forthe low-temperature, hot-melt resin layer is obtained.

According to the above mentioned formula, stir the long chain imidazolederivatives by a counting stirring machine to form a later use coatingstuff for the reinforcing layer.

According to the above mentioned formula, mixing butyl acrylate, methylacrylate and glycol acrylate in a reactor, under presence of tetramethylbutyl peroxy-2-ethyl hexanoate, a copolymer is formed. After stirringand foam breaking, a coating stuff to be used for the monomer layer isobtained.

A coating stuff to be used for the conductive particle layer, usesconductive particles and low-temperature, hot-melt, micro-encapsulatingresin for receiving the conductive particles. In present invention, theconductive particles can be Michael Robert (brand) AV conductiveparticles.

Coating processes are carried out under temperature of 100° C.-135° C.to successively form the conductive particle layer, low-temperature,hot-melt resin layer, the reinforcing layer, and the monomer layer.After 8 minutes, the four layers are coated onto an opal surface-treatedpolyester film. Roll up the polyester film isolated by an isolatingfilm. After slice the polyester film and re-roll up the polyester film,the functional multilayer anisotropic conductive adhesive film of thepresent invention is obtained.

In the present invention, the stirring machine adopts 3D multi-DOFstirring apparatus possessed by the applicant (Patent application No.200310111757). The stirring machine can set capturing and positioningparameters to adjusting stirring process. The stirring machine candetect viscosity, and render hot-melt resin, elastic mixture resin,monomer mixture solution, and conductive particle paste uniformlydistributed, and form a ropy layer on the surface of the ACAF, so as toprepare the anisotropic conductive adhesive film.

The anisotropic conductive adhesive film of the present invention can beapplied to connect LCD drive IC and high density FPC, downsizing andintegrating COF, TAB, COG IC chips, and capable of connecting IC filletswith 0.18 micron fillet distance or fillet width, which results in highproduction yield. The anisotropic conductive adhesive film of thepresent invention is a microelectronic bonding, packing, and functionalconnection technique, meeting preparation requirements of resin thermalcuring shrinkage, positioning/offset parameters, short circuit and ICdamage.

The multiple layered structure of the ACAF of the present invention canfacilitate bonding, packaging and connection between LCD,semiconductors, IC chips and FPC under 10 microns distance or width. Asa low temperature bonding stuff, the ACAF of the present invention islead free and environment protection, popular to be an assembly stuffadapting the environment and facilitating IC cards, high frequencydetectors, remote radio electronic labels to be functional andconvenient.

In connection between the ACAF of the present invention and fillets,resistance splicing sets up connection between protuberant electrodesand circuit, greatly reducing electrodes contact area, and providingsubstantial conductive particles to keep on-state status, meanwhileinsuring insulation between the electrodes. As far as the connectioninvolving micro spaces, the ACAF is divided into connection layer,insulation layer and on-state layer, the anisotropic conductive isproportional to quantity of conductive particles at each of theprotuberant electrodes. The connection layer, the insulation layer andthe on-state layer of the ACAF are respectively stratified and insulatedfrom one another, so the connection layer, insulation layer and on-statelayer are respectively independent. Comparing to conventional ACF, theACAF of the present invention has high conductive particle efficiency,high electrode capturing efficiency, and low loss of conductiveparticles between electrodes. Due to thermal expansion coefficient ofthe ACAF between IC chips and substrates, mechanical inner stressderived therefrom is buffered, at the same time improving viscositythereof. The ACAF can be applied for multiple layered components withimproved sensitivity of the connection, punching free, Lead free,halogen free, and solder free.

BRIEF DESCRIPTION OF THE DRAWINGS

No drawing is presented.

DETAILED DESCRIPTION OF CERTAIN EMBODIMENTS

While the subject invention will now be described in detail, it is doneso in connection with the illustrative embodiments. It is intended thatchanges and modifications can be made to the described embodimentswithout departing from the true scope and spirit of the subjectinvention as defined by the appended claims.

Basic formula for polymerization of the anisotropic conductive adhesivefilm of the present invention is listed as follow:

tocopheroxyl, YP-70, 10-30 parts by weight;

novolac epoxy, selected from the group consisting of F-55, F-51 andF-44, 10-20 parts by weight;

acrylic rubbers, 10-20 parts by weight;

an elastic mixture, 5-10 parts by weight;

long chain imidazole derivatives, 0.75-5 parts by weight;

a monomer in the monomer layer, 5-10 parts by weight per 500 parts bythe total weight of the anisotropic conductive adhesive film;

conductive particles, 30-40 parts by weight per 500 parts by totalweight of the anisotropic conductive adhesive film;

a solvent, prepared by mixing toluene and ethyl acetate with a weightratio of 4:6, and a solution is prepared with the reactant thereof by aweight concentration of 20%-40%;

the density of solution with conductive particles is 1.2 g/cm³; thesolution viscosity under temperature of 25° C. is 5000-10000 mPa·S.

Preferred Embodiment of the Present Invention

Processes for preparing the functional multilayer anisotropic conductiveadhesive film of the present invention, includes the following steps:mix the tocopheroxyl, YP-70, 20 parts by weight, and the solvent, 200parts by weight in a reactor. Dissolve and stir in the reactor, and addnovolac epoxy, 15 parts by weight. As the novolac epoxy completelydissolves, add elastic mixture, 5 parts by weight and continue stirringand dissolving. Add acrylic rubber, 20 parts by weight, and the solvent,200 parts by weight, stirring and dissolving. Stand by for later use.

Put long chain imidazole derivative 3 parts by weight in a reactor,stirring for 2 hours under temperature of 50° C. Set aside for lateruse.

Prepare 5 μm conductive particles, 30 part by weight, with reference tothe weight ratio of the anisotropic conductive adhesive film. A countingstirring apparatus stirs micro-encapsulating resin, and then combineconductive particles. Set aside for later use.

Prepare monomer solution, 10 parts by weight. Weight ratio of thecopolymer is 10%. Set aside for later use.

All the stirring operations are carried out by a 3D multi-DOF stirringapparatus.

Then, coating processes are respectively carried out on an opalsurface-treated polyester film under temperature of 100° C.-130° C.—120°C. for 6-8 minutes. The four layers are coated onto the opalsurface-treated polyester film. Roll up the polyester film and slice thepolyester film. Re-roll up the polyester film with 0.03 mm-0.015 mmwidth, and 50 meters long per roll of the ACAF.

In terms of the anisotropic conductive adhesive film obtained accordingto the preferred embodiment, parameters of FOG series after slicing theACAF is listed as following:

Type: DBL SOFG200 Product: FOG

Thickness: 20 μm

Length: 50/100 m/roll

Width: 1.5 mm

Conductive particle material: particles surface gold plating

Density of conductive particles: 48 10 k/mm³

Minimum space capacity: 50 pitch

Conditions of Preloading:

Temperature: 85° C.±5° C.

Pressure: 1.2 mpa

Time: 2 seconds

Loading Condition:

Temperature: 187° C.

Pressure: 0.13 mPa

Time: 18 seconds

FOG Outcome:

On-state resistance: 1.2Ω

Insulation resistance: 1012

Bonding intensity: 60N/m

Storage time: 7 months/−10-5° C.

Pass rate: 99%

Alternative Embodiment of the Present Invention

Processes for preparing functional multilayer anisotropic conductiveadhesive film of the present invention, includes the following steps:mix the tocopheroxyl, YP-70, 20 parts by weight, and the solvent, 200parts by weight in a reactor. Dissolve and stir in the reactor andadding novolac epoxy, 15 parts by weight. As the novolac epoxycompletely dissolves, add elastic mixture, 5 parts by weight andcontinuing stirring and dissolving. Add acrylic rubber, 20 parts byweight, and the solvent, 200 parts by weight, stirring and dissolving.Stand by for later use.

Put a long chain imidazole derivative 3 parts by weight in a reactor,stirring for 2 hours under temperature of 50° C. Set aside for lateruse.

Prepare 4 μm conductive particles, 30 part by weight, with reference tothe weight ratio of the anisotropic conductive adhesive film. Themicro-encapsulating resin is used for micro encapsulating the conductiveparticles. Set aside for later use.

Prepare a monomer solution, 10 parts by weight. Weight ratio of thecopolymer is 20%. Set aside for later use.

All the stirring operations are carried out by a 3D multi-DOF stirringapparatus.

Then, coating processes are respectively carried out on an opalsurface-treated polyester film under temperature of 100° C.-130° C.—135°C. for 6-8 minutes. The four layers are coated onto the opalsurface-treated polyester film. Roll up the polyester film and slice thepolyester film. Re-roll up the polyester film with 0.03 mm-0.015 mmwidth, and 50 meters long per roll of the ACAF.

In terms of the anisotropic conductive adhesive film obtained accordingto the alternative embodiment, parameters of COF series after slicingthe ACAF is listed as following:

Type: DBL 40CT Product: COF

Thickness: 23 μm

Length: 50/100 m/roll

Width: 1.5-6 mm

Conductive particle size: 4 μm

Density of conductive particles: 130 10 k/mm³

Minimum space capacity: 30 pitch

Conditions of Preloading:

Temperature: 85° C.±5° C.

Pressure: 1 mpa

Time: 5 seconds

Loading Condition:

Temperature: 205° C.

Pressure: 50 mPa

Time: 16 seconds

COF Outcome:

On-state resistance: >0.2Ω

Insulation resistance: 1012

Bonding intensity: 60N/m

Storage time: 6 months/−10-5° C.

Pass rate: 99%

Third Embodiment of the Present Invention

Processes for preparing functional multilayer anisotropic conductiveadhesive film of the present invention, includes the following steps:mix the tocopheroxyl, YP-70, 20 parts by weight, and the solvent, 200parts by weight in a reactor. Dissolve and stir in the reactor andadding novolac epoxy, 15 parts by weight. As the novolac epoxycompletely dissolves, add elastic mixture, 5 parts by weight andcontinue stirring and dissolving. Add acrylic rubber, 20 parts byweight, and the solvent, 200 parts by weight, stirring and dissolving.Stand by for later use.

Put a long chain imidazole derivative 3 parts by weight in a reactor,stirring for 2 hours under temperature of 50° C. Set aside for lateruse.

Prepare 3 μm conductive particles, 30 part by weight, with reference tothe weight ratio of the anisotropic conductive adhesive film. Themicro-encapsulating resin is used for micro encapsulating the conductiveparticles. Set aside for later use.

Prepare a monomer solution, 10 parts by weight. Weight ratio of thecopolymer is 30%. Set aside for later use.

All the stirring operations are carried out by a 3D multi-DOF stirringapparatus.

Then, coating processes are respectively carried out on an opalsurface-treated polyester film under temperature of 100° C.-130° C.—120°C. for 6-8 minutes. The four layers are coated onto the opalsurface-treated polyester film. Roll up the polyester film and slice thepolyester film. Re-roll up the polyester film with 0.03 mm-0.015 mmwidth, and 50 meters long per roll of the ACAF.

In terms of the anisotropic conductive adhesive film obtained accordingto the third embodiment, parameters of COG series after slicing the ACAFis listed as following:

Type: DBL-30CG Product: COG

Thickness: 30 μm

Length: 50/100 m/roll

Width: 1.5 mm

Conductive particle size: 3 μm

Density of conductive particles: 180 10 k/mm³

Minimum space capacity: 15 μm-20 μm

Conditions of Preloading:

Temperature: 85° C.±5° C.

Pressure: 1 mpa

Time: 3 seconds

Loading Condition:

Temperature: 210° C.

Pressure: 60 mPa

Time: 19 seconds

COG Outcome:

On-state resistance: >0.1Ω

Insulation resistance: 1012

Bonding intensity: 60N/m

Storage time: 5 months/−10-5° C.

Pass rate: 99%

First Comparison Example to the Present Invention

Processes for preparing functional multilayer anisotropic conductiveadhesive film, includes the following steps: mix the tocopheroxyl,YP-70, 20 parts by weight, and the solvent, 200 parts by weight in areactor. Dissolve and stir in the reactor and adding novolac epoxy, 15parts by weight. Add acrylic rubber, 20 parts by weight, and thesolvent, 200 parts by weight, stirring and dissolving. Stand by forlater use.

Put a long chain imidazole derivative 3 parts by weight in a reactor,stirring for 2 hours under temperature of 50° C. Set aside for lateruse.

Prepare 5 μm conductive particles, 30 part by weight, with reference tothe weight ratio of the anisotropic conductive adhesive film. Themicro-encapsulating resin is used for micro encapsulating the conductiveparticles. Set aside for later use.

Prepare a monomer solution, 10 parts by weight. Weight ratio of thecopolymer is 10%. Set aside for later use.

All the stirring operations are carried out by a 3D multi-DOF stirringapparatus.

Then, coating processes are respectively carried out on an opalsurface-treated polyester film under temperature of 100° C.-130° C.—120°C. for 6-8 minutes. The four layers are coated onto the opalsurface-treated polyester film. Roll up the polyester film and slice thepolyester film. Re-roll up the polyester film with 0.03 mm-0.015 mmwidth, and 50 meters long per roll of the ACAF.

In the first comparison example, the styrene-butadiene rubber isexcluded, and the monomer solution is adjusted. In terms of theanisotropic conductive adhesive film obtained according to the firstcomparison embodiment, parameters of FOG series after slicing the ACAFis listed as following:

Type: DBL SOFG200 Product: FOG

Thickness: 20 μm

Length: 50/100 m/roll

Width: 1.5 mm

Conductive particle material: conductive gold

Density of conductive particles: 48 10 k/mm³

Minimum space capacity: 50 pitch

Conditions of Preloading:

Temperature: 85° C.±5° C.

Pressure: 1.2 mpa

Time: 2 seconds

Loading Condition:

Temperature: 187° C.

Pressure: 0.13 mPa

Time: 18 seconds

FOG Outcome:

On-state resistance: 1.0Ω

Insulation resistance: 1011

Bonding intensity: 30N/m

Storage time: 5 months/−10-5° C.

Pass rate: 30%

Second Comparison Example to the Present Invention

Processes for preparing functional multilayer anisotropic conductiveadhesive film, includes the following steps: mix the tocopheroxyl,YP-70, 20 parts by weight, and the solvent, 200 parts by weight in areactor. Dissolve and stir in the reactor and adding novolac epoxy, 15parts by weight. As the novolac epoxy completely dissolves, add elasticmixture, 5 parts by weight and continuing stirring and dissolving. Addacrylic rubber, 20 parts by weight, and the solvent, 200 parts byweight, stirring and dissolving. Stand by for later use.

Put a long chain imidazole derivative 3 parts by weight in a reactor,stirring for 2 hours under temperature of 50° C. Set aside for lateruse.

Prepare 4 μm conductive particles, 30 part by weight, with reference tothe weight ratio of the anisotropic conductive adhesive film. Themicro-encapsulating resin is used for micro encapsulating the conductiveparticles. Set aside for later use.

All the stirring operations are carried out by a 3D multi-DOF stirringapparatus.

Then, coating processes are respectively carried out on an opalsurface-treated polyester film under temperature of 100° C.-130° C.—120°C. for 6-8 minutes. The four layers are coated onto the opalsurface-treated polyester film. Roll up the polyester film and slice thepolyester film. Re-roll up the polyester film with 0.03 mm-0.015 mmwidth, and 50 meters long per roll of the ACAF.

In the second comparison example, the monomer solution is excluded. Interms of the anisotropic conductive adhesive film obtained according tothe Second comparison embodiment, parameters of COF series after slicingthe ACAF is listed as following:

Type: DBL-40CT Product: COF

Thickness: 23 μm

Length: 50/100 m/roll

Width: 1.5-6 mm

Conductive particle size: 4 μm

Density of conductive particles: 130 10 k/mm³

Minimum space capacity: 30 pitch

Conditions of Preloading:

Temperature: 85° C.±5° C.

Pressure: 1 mpa

Time: 5 seconds

Loading Condition:

Temperature: 205° C.

Pressure: 1 mPa

Time: 5 seconds

COF Out Come:

On-state resistance: >0.7Ω

Insulation resistance: 108

Bonding intensity: 40N/m

Storage time: 5 months/−10-5° C.

Pass rate: 90%

Third Comparison Example to the Present Invention

Processes for preparing functional multilayer anisotropic conductiveadhesive film, includes the following steps: mix the tocopheroxyl,YP-70, 20 parts by weight, and the solvent, 200 parts by weight in areactor. Dissolve and stir in the reactor and adding novolac epoxy, 15parts by weight. As the novolac epoxy completely dissolves, add elasticmixture, 5 parts by weight and continue stirring and dissolving. Add thesolvent, 200 parts by weight, stirring and dissolving. Stand by forlater use.

Put a long chain imidazole derivative 3 parts by weight in a reactor,stirring for 2 hours under temperature of 50° C. Set aside for lateruse.

Prepare 3 μm conductive particles, 30 part by weight, with reference tothe weight ratio of the anisotropic conductive adhesive film. Themicro-encapsulating resin is used for micro encapsulating the conductiveparticles. Set aside for later use.

Prepare a monomer solution, 10 parts by weight. Weight ratio of thecopolymer is 30%. Set aside for later use.

All the stirring operations are carried out by a 3D multi-DOF stirringapparatus.

Then, coating processes are respectively carried out on an opalsurface-treated polyester film under temperature of 100° C.-130° C.—120°C. for 6-8 minutes. The four layers are coated onto the opalsurface-treated polyester film. Roll up the polyester film and slice thepolyester film. Re-roll up the polyester film with 0.03 mm-0.015 mmwidth, and 50 meters long per roll of the ACAF.

In the third comparison example, the acrylic rubber is excluded. Interms of the anisotropic conductive adhesive film obtained according tothe third comparison embodiment, parameters of COG series after slicingthe ACAF is listed as following:

Type: DBL-30CG Product: COG

Thickness: 30 μm

Length: 50/100 m/roll

Width: 1.5 mm

Conductive particle size: 3 μm

Density of conductive particles: 180 10 k/mm³

Minimum space capacity: 15 μm-20 μm

Conditions of Preloading:

Temperature: 85° C.±5° C.

Pressure: 1 mpa

Time: 3 seconds

Loading Condition:

Temperature: 210° C.

Pressure: 60 mPa

Time: 19 seconds

COG Outcome:

On-state resistance: >0.1Ω

Insulation resistance: 1011

Bonding intensity: 10N/m

Storage time: 7 days/−10-5° C.

Pass rate: 0

Having thus described particular embodiments of the invention, variousalterations, modifications, and improvements will readily occur to thoseskilled in the art. Such alterations, modifications and improvements asare made obvious by this disclosure are intended to be part of thisdescription though not expressly stated herein, and are intended to bewithin the spirit and scope of the invention. Accordingly, the foregoingdescription is by way of example only, and not limiting. The inventionis limited only as defined in the following claims and equivalentsthereto.

1. A functional multilayer anisotropic conductive adhesive filmcomprising: a copolymer layer, comprising a copolymer of butyl acrylate,methyl acrylate, and glycol acrylate, made under presence of tetramethylbutyl peroxy-2-ethyl hexanoate; a reinforcing layer, comprising longchain imidazole derivatives, which are formed by a synthesis of2,4-diamino-6-[-2-undecyl imidazolyl (1)]-ethyl-cis-triazine,1-cyanoethyl-2-undecyl-imidazole trimellitate, and isocyanatederivative; a resin layer, comprising a polymer of tocopheroxyl, novolacepoxy, acrylic rubbers and an elastic mixture of acrylic rubbers andstyrene-butadiene rubbers; and a conductive particle layer, comprisingconductive particles and micro-encapsulating resin for receiving theconductive particles, wherein the diameter of the conductive particlesis selected from the group consisting of 3.00 μm±0.05, 3.25 μm±0.05,3.50 μm±0.05, 3.75 μm±0.05 and 4.00 μm±0.05; wherein the copolymerlayer, the reinforcing layer, the resin layer and the conductiveparticle layer are successively bonded by coating and drying processes.2. The functional multilayer anisotropic conductive adhesive film as inclaim 1, wherein in polymerization of the resin layer, the tocopheroxylis present in an amount of 10-30 parts by weight; the novolac epoxy ispresent in an amount of 10-20 parts by weight; bulk density of theacrylic rubbers is 0.48±0.1 g/cc, volatility<1.0%, Tg−30° C., and theacrylic rubbers are present in an amount of 10-20 parts by weight;wherein the elastic mixture is present in an amount of 5-10 parts byweight; and wherein the long chain imidazole derivatives are present inan amount of 0.75-5 parts by weight.
 3. The functional multilayeranisotropic conductive adhesive film as in claim 2, wherein the contentof the conductive particles is 30-40 parts by weight per 500 parts bytotal weight of the anisotropic conductive adhesive film.
 4. Thefunctional multilayer anisotropic conductive adhesive film as in claim2, wherein the content of the conductive particles is 5-10 parts byweight per 500 parts by the total weight of the anisotropic conductiveadhesive film, and wherein the weight ratio of the butyl acrylate, themethyl acrylate, the glycol acrylate, and the tetramethyl butylperoxy-2-ethyl hexonate is set in 7:3:2:1.
 5. The functional multilayeranisotropic conductive adhesive film as in claim 1, wherein the contentof the conductive particles is 30-40 parts by weight per 500 parts bytotal weight of the anisotropic conductive adhesive film.
 6. Thefunctional multilayer anisotropic conductive adhesive film as in claim1, wherein the content of the conductive particles is 5-10 parts byweight per 500 parts by the total weight of the anisotropic conductiveadhesive film, and wherein weight ratio of the butyl acrylate, themethyl acrylate, the glycol acrylates, and the tetramethyl butylperoxy-2-ethyl hexonate is set in 7:3:2:1.
 7. The functional multilayeranisotropic conductive adhesive film as in claim 1 made by a preparationmethod, adopting suspension polymerization means, comprising thefollowing steps: A, mixing and stirring said tocopheroxyl, said novolacepoxy, and solvent; B, adding said acrylic rubbers and said elasticmixture of acrylic rubbers and styrene-butadiene rubbers into theadmixture obtained from step A, stirring; C, adding said acrylic rubbersand solvent into the admixture obtained from step B, dissolving andstirring; D, waiting as viscosity of the polymer obtained from step Cnaturally reduces to a degree that no more polymerization occurs, thus acoating material to be used for said resin layer is obtained; E,stirring said long chain imidazole derivatives to form a coatingmaterial to be used for said reinforcing layer; F, stirring saidmicro-encapsulating resin, and then combining said conductive particleswith said microencapsulating resin in said conductive particle layer; G,mixing said butyl acrylate, said methyl acrylate and said glycolacrylate under presence of said tetramethyl butyl peroxy-2-ethylhexanoate to form said copolymer; after stirring and foam breaking, acoating material to be used for said copolymer later is obtained; H,coating under temperature of 100° C.-135° C. to successively form theconductive particle layer, the resin layer, the reinforcing layer, andthe copolymer layer on an opal surface-treated polyester film, therebyobtaining the functional multilayer anisotropic conductive adhesivefilm.
 8. The functional multilayer anisotropic conductive adhesive filmas in claim 7 made by a preparation method wherein, the tocopheroxyl ispresent in an amount of 10-30 parts by weight; the novolac epoxy ispresent in an amount of 10-20 parts by weight; bulk density of theacrylic rubbers is 0.48±0.1 g/cc, volatility <1.0%, Tg−30° C., solutionviscosity under temperature of 25° C. is 5000-10000 mPa·S, and theacrylic rubbers are present in an amount of 10-20 parts by weight;wherein the styrene-butadiene rubbers in the elastic mixture haveparameters as follows: Mooney viscosity of natural rubber ML100° C.(1+4): 45-55%, stretching stress 300% (35 minutes): 14.1-18.6 MPa,tensile strength at a given elongation (35 minutes): >23.7 MPa, and,elongation at break (35 minutes): >415%; wherein the elastic mixture ispresent in an amount of 5-10 parts by weight; wherein the long chainimidazole derivatives are present in an amount of 0.75-5 parts byweight; wherein the diameter of the conductive particles is selectedfrom the group consisting of 3.00 μm±0.05, 3.25 μm±0.05, 3.50 μm±0.05,3.75 μm±0.05 and 4.00 μm±0.05, and the content of the conductiveparticles is 30-40 parts by weight per 500 parts by total weight of theanisotropic conductive adhesive film; wherein the content of saidcopolymer of said copolymer layer is 5-10 parts by weight per 500 partsby the total weight of the anisotropic conductive adhesive film, whereinweight ratio of the butyl acrylate, the methyl acrylate, the glycolacrylates, and the tetramethyl butyl peroxy-2-ethyl hexanoate is set in7:3:2:1.
 9. The functional multilayer anisotropic conductive adhesivefilm as in claim 8 made by a preparation method wherein the long chainimidazole derivatives in the reinforcing layer are obtained by thefollowing processes: mixing the 2,4-diamino-6-[-2-undecylimidazolyl(1)]-ethyl-cis-triazine, and the1-cyanoethyl-2-undecyl-imidazole trimellitate with a weight ratio of1:1, reacting for 3 hours, and then heating reactant from the mixingprocess up to 50° C., adding toluene-2,4-diisocyanate and a solvent intothe reactant from the mixing process with a weight ratio of 0.8:60:30,and reacting for 5 hours.
 10. The functional multilayer anisotropicconductive adhesive film as in claim 8 made by a preparation methodwherein the thermal aging property of the elastic mixture is improved bysteps of: mixing and preparing the acrylic rubbers and thestyrene-butadiene rubbers with weight ratio of 10:5, and then physicallyadmixing trace meta-alkaline reinforcing agent containing silica, silanecoupling agent, and quaternary ammonium salt, in accordance with aweight ratio of 1:0.2:0.3.
 11. The functional multilayer anisotropicconductive adhesive film as in claim 8 made by a preparation methodwherein the solvent is obtained by mixing toluene and ethyl acetate witha weight ratio of 4:6, and a solution is prepared with the reactantthereof by a weight concentration of 20%-40%.
 12. The functionalmultilayer anisotropic conductive adhesive film as in claim 7 made by apreparation method wherein the long chain imidazole derivatives in thereinforcing layer are obtained by the following processes: mixing2,4-diamino-6-[-2-undecyl imidazolyl(1)]-ethyl-cis-triazine, and1-cyanoethyl-2-undecyl-imidazole trimellitate with a weight ratio of1:1, reacting for 3 hours, and then heating reactant from the mixingprocess up to 50° C., adding toluene-2,4-diisocyanate and a solvent intothe reactant from the mixing process with a weight ratio of 0.8:60:30,and reacting for 5 hours.
 13. The functional multilayer anisotropicconductive adhesive film as in claim 7 made by a preparation methodwherein the thermal aging property of the elastic mixture is improved bysteps of: mixing and preparing the acrylic rubbers and thestyrene-butadiene rubbers with weight ratio of 10:5, and then physicallyadmixing trace meta-alkaline reinforcing agent containing silica, silanecoupling agent, and quaternary ammonium salt, in accordance with aweight ratio of 1:0.2:0.3.
 14. The functional multilayer anisotropicconductive adhesive film as in claim 7 made by a preparation methodwherein the solvent is obtained by mixing toluene and ethyl acetate witha weight ratio of 4:6, and a solution is prepared with the reactantthereof by a weight concentration of 20%-40%.